This invention relates generally to sewing machines. More particularly, the present invention relates to a hem stitching presser foot used in combination with a sewing machine.
Hem stitches are generally formed with threads which comprise a first portion located in the fabric when a needle penetrates the fabric, and a second portion located on the outside of the fabric edge. Often a standard zig-zag sewing machine action is utilized to hem the edge of a piece of fabric in order to prevent fabric fraying and to create a uniform sewn edge.
In a hem stitching operation it is usually desirable to provide stitches of uniform width and separation. It is known, however, that hem stitching operations carried out in a conventional manner often result in skipped stitches and thread severance. As pointed out in U.S. Pat. No. 4,473,019 (the contents of which are incorporated herein), skipped stitches have resulted from the fact that a loop taker hook often fails to catch a thread loop, and thread severance has resulted from the fact that the upper thread tends to be disordered as it is pulled up by a thread take-up lever due to the absence of the base fabric against the point of the needle. The above-mentioned patent provides a hem stitching presser foot for sewing machines which provides friction to the thread as it passes outside of the fabric edge, to thereby ensure a more uniform stitch pattern.
In addition to normal zig-zag hem stitches, it is desirable in some instances to provide a different type of hem stitch for aesthetic and/or functional reasons. More particularly, sometimes is it desirable to provide a satin stitch hem along the edge of a piece of fabric. A satin stitch is distinguishable from the normal zig-zag stitch in that the successive loops of thread lie substantially adjacent to or on top of one another to form a continuous border of hem threads.
Accordingly, there has been a need for a novel adjustable satin stitch presser foot which can be used in connection with virtually all types of zig-zag sewing machines, and which is capable of efficiently producing a desired satin stitch hem. Such a novel presser foot should provide stitches of uniform width and length, and be capable of use with a wide variety of thread types. Additionally, a satin stitch presser foot is needed which requires little skill to use, and permits use of the presser foot with a wide variety of fabric types. Moreover, a novel satin stitch presser foot is needed which has the ability to quickly hem around a sharp corner of a piece of fabric, such as the corner of a napkin or tablecloth. The present invention fulfills these needs and provides other related advantages.